Hi,

I am running a solis s6 8kw pro inverter with 3 pylontech us3000 batteries. Looking to upgrade to a bigger battery, any recommendations? Looking to to 14 or 16kw battery.

Thank you

1 hour ago, Shockin said:

Looking to to 14 or 16kw battery.

Think about handling, i.e in case of requirement to move them. A 4.8kWh battery weights about 45kg. 2 persons can handle this but everything larger would require lifting devices. Better make up your storage needs with several handy units. Also in case of failure of one it would impact the system less.

9 hours ago, Shockin said:

Looking to to 14 or 16kw battery.

DiY, I'd say, get some (16 or 32, depending on kWh wanted) 314Ah EVE cells, a 150A or larger JK BMS (or two, depending on the amount of batteries involved, normally 16cells per battery) and voilla, mine is compressed, but not enclosed, in the garage on a angled steel narrow structure, with ply wood as the base for the batteries to sit on... not planning on moving them, but if I must, then I will break down the batteries and move the cells individually to their new home...

Or the SHOTO 10-Box 5 stacked and secured bit diffrent to rack mounting but maybe gives you better ventilation.

On 2025/12/10 at 9:25 PM, Shockin said:

14 or 16kw battery.

Here is your battery in modular form 15kwh nice for scalability

11 hours ago, TaliaB said:

Here is your battery in modular form 15kwh nice for scalability

Looks nice and need. How high can you go considering the wight of the packs?

There is one problem: In case you have to move one of the lover packs i.e. for inspection or maintenance, you would have to first take the packs above off. I prefer it this way:

33 minutes ago, Beat said:

I prefer it this way

all your cells are lying on their side, which may, or may not be a good, thing... those battery boxes of yours are supposed to go into a 19" rack and then the cells would be upright...

2 hours ago, Kalahari Meerkat said:

all your cells are lying on their side, which may, or may not be a good, thing... those battery boxes of yours are supposed to go into a 19" rack and then the cells would be upright...

Giter batteries rack mounted have their batteries on their sides. I don't think this is a consideration.

It would be interesting to know if I am dreaming😀

8 hours ago, Beat said:

How high can you go considering the wight of the packs?

Not sure but the Shoto is a 19 inch rack design, Rack-type modules generally don’t have a strict “max stack height” The FW e tower are allowed to be stacked 6 high they use a solid very solid pedestal between each battery but strictly max 6 stacking allowed.

In a certified rack battery module, the manufacturer has already designed the internal support, compression, and venting for the module to work in the rack position. If the module is certified for rack use, it is certified to run horizontally.

@Beat Your method is not a problem as you have 19 inch rack design modules.

10 hours ago, Kalahari Meerkat said:

all your cells are lying on their side, which may, or may not be a good, thing..

The importer and seller, Averge, confirmed to me that this way of installation presents no problems.

By the way - as I think of it, it's the other way around. As the picture of an opened pack shows the cells lie flat if the pack is installed horizontally. In my vertical installation half of the cells are upright, the other half upside down.

On the flat positioned opened pack the cells terminals are visible with the metal plate bridges between the cells.

Edited December 13, 2025Dec 13 by Beat

On 2025/12/12 at 10:32 AM, Beat said:

Looks nice and need. How high can you go considering the wight of the packs?

There is one problem: In case you have to move one of the lover packs i.e. for inspection or maintenance, you would have to first take the packs above off. I prefer it this way:

The batteries in the middle work harder than the ones at the ends. This photo does not show battery cable lengths should be.

I agree with @frivan . Solution 1. Busbar on pos and neg diagonal take off to battery disconnect. Solution 2. Diagonal cable take off. Positive from battery 1 to pos side of disconnect. Negative from battery 6 to neg side of discconect. Equal length inter battery jumpers.

Edited December 13, 2025Dec 13 by TaliaB

Beat, read this tech note regarding cable lengths and importance of using the same thickness cable for all the batteries

Edited December 13, 2025Dec 13 by giorgos

19 hours ago, frivan said:

The batteries in the middle work harder than the ones at the ends. This photo does not show battery cable lengths should be.

This myth seems to be persistent. We discussed this several times. The fact is that differences in internal resistance (Ri) between the packs are likely to be higher than 20cm of 25mm² connection cables. As a matter of fact it happens so that the pack at the end of the row (and it's the oldest one) draws the highest currents due to its lower Ri.

These differences in Ri are due to manufacturing tolerances.

Edited December 14, 2025Dec 14 by Beat

43 minutes ago, Beat said:

This myth seems to be persistent. We discussed this several times.

You’re right that pack Ri varies and can exceed a short length of cable. The issue is that Ri variation is random and time-dependent, while wiring resistance is fixed and directional. Adding a systematic wiring imbalance does not cancel Ri spread it stacks with it.

Balanced cabling (busbars or diagonal take-off) doesn’t eliminate Ri differences, but it ensures wiring does not bias current sharing on top of them, which is why all lithium manufacturers still specify symmetrical layouts.

9 hours ago, TaliaB said:

You’re right that pack Ri varies and can exceed a short length of cable. The issue is that Ri variation is random and time-dependent, while wiring resistance is fixed and directional. Adding a systematic wiring imbalance does not cancel Ri spread it stacks with it.

Balanced cabling (busbars or diagonal take-off) doesn’t eliminate Ri differences, but it ensures wiring does not bias current sharing on top of them, which is why all lithium manufacturers still specify symmetrical layouts.

Your thoughts are basically correct. However the resistances of 25mm² cabling is so low compared to the packs Ri that it is neglectable. Remember that the cells Ri in a pack add up to the packs Ri. The more cells you have the higher the Ri. Therefor your consideration is more relevant on 12V and 24V batteries but becomes less important on 48V and 51V batteries.

Edited December 14, 2025Dec 14 by Beat

1 hour ago, Beat said:

Your thoughts are basically correct. However the resistances of 25mm² cabling is so low compared to the packs Ri that it is neglectable. Remember that the cells Ri in a pack add up to the packs Ri. The more cells you have the higher the Ri. Therefor your consideration is more relevant on 12V and 24V batteries but becomes less important on 48V and 51V batteries.

Agreed that at 48–51 V the resistance of short 25 mm² links is small compared to pack Ri, and the effect is far less critical than at 12/24 V.

The reason balanced cabling is still recommended is not magnitude but directionality: pack Ri is random and time-varying, while wiring resistance is fixed and always biases current the same way. Removing that systematic bias ensures current sharing is determined only by unavoidable Ri differences, which is why manufacturers still specify symmetrical layouts at 48 V.

Cable resistance at 48 V is small relative to pack Ri. Hallway wiring will usually work.
Problems are not immediate.
Hallway wiring introduces a fixed directional bias.
Balanced wiring removes that bias entirely.
This is why it remains best practice

Edited December 14, 2025Dec 14 by TaliaB

Only 2 methods i use for lfp.power wiring 12v,24v or 48/51v.

By far the best option but not always possible.

Alternatively this option for lfp.

On 12/15/2025 at 12:16 AM, TaliaB said:

resistance is fixed and always biases current

what is the usual range for cables R ? , I have 35 mm for 48 V 350 Ah battery , and the drop voltage is 0.1 but it goes up to 0.3 when charging or discharging with higher current , I believe the drop voltage is more than ok but the variation worries me

39 minutes ago, esmail-kassir said:

what is the usual range for cables R ? , I have 35 mm for 48 V 350 Ah battery , and the drop voltage is 0.1 but it goes up to 0.3 when charging or discharging with higher current , I believe the drop voltage is more than ok but the variation worries me

It would be interesting to know your method of measuring the voltdrop in your system. Like the saying goes tell me yours and I will tell you mine😂

1 hour ago, TaliaB said:

It would be interesting to know your method of measuring the voltdrop in your system. Like the saying goes tell me yours and I will tell you mine😂

well , It is not smart method to be proud about🤭

I read (inverter screen battery voltage) - (battery screen voltage)

2 hours ago, esmail-kassir said:

what is the usual range for cables R ? , I have 35 mm for 48 V 350 Ah battery , and the drop voltage is 0.1 but it goes up to 0.3 when charging or discharging with higher current , I believe the drop voltage is more than ok but the variation worries me

Volt drop is linier to the current passing. No problem with 0.1 to 0.3.

I would be more concerned about the cable size for the 350Ah unless you are using a fuse/MCB or current is limited by another devise to around 125/160A?

1 hour ago, Scorp007 said:

Volt drop is linier to the current passing. No problem with 0.1 to 0.3.

I would be more concerned about the cable size for the 350Ah unless you are using a fuse/MCB or current is limited by another devise to around 125/160A?

the inverter is 5000 W

so maximum charge and discharge is 100 A

On 2025/12/10 at 9:25 PM, Shockin said:

Hi,

I am running a solis s6 8kw pro inverter with 3 pylontech us3000 batteries. Looking to upgrade to a bigger battery, any recommendations? Looking to to 14 or 16kw battery.

Thank you

A good thing about pylontech is that you can mix and match different size individual batteries. So you could add a combination of 3000s and/or 5000s to the existing 9kWh bank.

A good thing about having several small batteries connected together in a bank is that if one of the batteries has to go back to the dealer to be looked at, you still have the rest of the bank available. I like FreedomWon. I have a 10/8. But it's one big battery. If anything goes wrong I've got to live without a battery or buy a replacement (really should be another 10/8 so that I can eventually run the two in parallel. That's not the cheapest way of doing things).

8 hours ago, esmail-kassir said:

well , It is not smart method to be proud about🤭

I read (inverter screen battery voltage) - (battery screen voltage)

No problem with your method at least you are on top of things by monotoring your system for deviations. Accessive heat in cables and safety devices is a telltale of high resistance at moderate to high battery current.

Voltage drop per meter (single conductor)

■ 25 mm² copper
Resistance: 0.00070 Ω/m
Voltage drop: 0.70 mV per amp per meter

■ 35 mm² copper
Resistance: 0.00050 Ω/m
Voltage drop: 0.50 mV per amp per meter

■ 50 mm² copper
Resistance: 0.00035 Ω/m
Voltage drop: 0.35 mV per amp per meter

Practical round-trip voltage drop (per meter of cable run)

Cable size mV/A/m (round trip)

25 mm² 1.40 mV/A/m

35 mm² 1.00 mV/A/m

50 mm² 0.70 mV/A/m

Installer rule-of-thumb (48 V systems)

Aim for <0.25–0.30 V total DC drop

That usually means:

≤1.5 m with 25 mm² @ 100 A

≤2 m with 35 mm² @ 150 A

≤2 m with 50 mm² @ 200 A

*Method: Use DMM on mV scale.

Measure total drop

Battery + to inverter +

Battery – to inverter –

Write both values down.

Work component by component:

Across positive fuse

Across positive breaker

Across positive cable sections

Across contactors / busbars

Repeat on negative side

Any point showing unusually high mV is your problem.

Cables (under load) 75% of inverter rating.

Excellent: <0.5%

Acceptable: <1%

Problematic: >1.5%